feat: modernize PSO and add convergence research

Migrate the package and examples to the tensor-native PyTorch implementation, add benchmark evidence, and add the guarded post-training convergence protocol with TensorBoard progress monitoring and hash-verified recovery.

Constraint: Preserve one-shot official-test sealing and auditable research artifacts

Rejected: Commit local .omc runs and downloaded datasets | multi-gigabyte runtime state is machine-local

Confidence: high

Scope-risk: broad

Not-tested: Production CUDA run on pieroot-server

.github/workflows/pypi.yml

@@ -1,38 +1,55 @@
-name: PyPI package
+name: Publish to PyPI
 
 on:
   push:
-    paths:
-      - "setup.py"
-      - "pso/__init__.py"
+    tags:
+      - "v*"
 
 permissions:
   contents: read
-  packages: write
 
 jobs:
-  build-linux:
+  test:
     runs-on: ubuntu-22.04
     strategy:
-      max-parallel: 5
       matrix:
-        python-version: ["3.9"]
+        python-version: ["3.10", "3.11"]
 
     steps:
-      - uses: actions/checkout@v3
-      - name: Set up Python
-        uses: actions/setup-python@v3
+      - uses: actions/checkout@v4
+      - name: Install uv and Python ${{ matrix.python-version }}
+        uses: astral-sh/setup-uv@v9
         with:
+          version: "0.12.7"
           python-version: ${{ matrix.python-version }}
-      - name: Install dependencies
-        run: |
-          python -m pip install --upgrade pip
-          if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
-          pip install setuptools wheel twine
-      - name: Build and publish
-        env:
-          TWINE_USERNAME: __token__
-          TWINE_PASSWORD: ${{ secrets.PYPI_TOKEN }}
-        run: |
-          python setup.py bdist_wheel sdist
-          twine upload dist/*.whl dist/*.tar.gz
+          enable-cache: true
+      - name: Sync dependencies
+        run: uv sync --locked --group dev
+      - name: Run tests
+        run: uv run --no-sync pytest -q
+      - name: Build package
+        run: uv build
+      - name: Check package distribution
+        run: uv run --no-sync twine check dist/*
+
+  publish:
+    needs: test
+    runs-on: ubuntu-22.04
+    steps:
+      - uses: actions/checkout@v4
+      - name: Install uv and Python 3.11
+        uses: astral-sh/setup-uv@v9
+        with:
+          version: "0.12.7"
+          python-version: "3.11"
+          enable-cache: true
+      - name: Sync dependencies
+        run: uv sync --locked --group dev
+      - name: Build package
+        run: uv build
+      - name: Check package distribution
+        run: uv run --no-sync twine check dist/*
+      - name: Publish package to PyPI
+        uses: pypa/gh-action-pypa-publish@release/v1
+        with:
+          password: ${{ secrets.PYPI_TOKEN }}